Means and system for tie-down



Se t. 23, 1969 J. A, BJORKSTEN ET AL 3,467,999

MEANS AND SYSTEM FOR TIE-DOWN Filed Oct. 5, 1967 United States Patent 3,467,999 MEANS AND SYSTEM FOR TIE-DOWN Johan A. Bjorksten, Fitchburg, Wis., and William A.

Kaufman, Alvin, Tex., assignors to Grilfolyn Company,

Inc., a corporation of Delaware Filed Oct. 5, 1967, Ser. No. 673,122 Int. Cl. A44b 21/00; A45f 1/16, 1/18 US. Cl. 24245 11 Claims ABSTRACT OF THE DISCLOSURE Tie down system typically comprising a flexible U formed member with holes in both ends which may be aligned and fastened together by binding means; and a separate spreading means, typically a plastic disc for spreading the sheet material to be tied down, so that it can be clamped and tied from the said U-formed member.

This invention relates to means for fastening high strength flexible sheet material, such as reinforced plastic from any point on such sheet material, and to a system comprising flexible sheet material so held.

Heretofore many types of clamps, grommets, loop-andball, button, and other types of fasteners have been used. However, none of these have possessed at the same time the property of being attachable at any point of a sheet without preparation, of holding pulls up to 100 lbs. per fastener and more, and of being mass producible at loW cost. The present invention provides a means for accomplishing this.

An object of this invention is a novel fastener for sheet material.

Another object is a tie-down device for tying flexible sheet material to the desired protective position.

Another object is a cover system of reinforced plastic film, comprising such fasteners.

Further objects will become apparent as the following detailed description proceeds.

In accordance with a preferred embodiment of our invention, we attach to a sheet of plastic film a rope, by means of a disc and an open bi-terminally perforated hook in the manner explained below and illustrated by the drawings, of which FIG. 1 is a top view of the hook, FIG. 2 a sectional side view of the hook, FIG. 3 a sectional side view of the hook, with rope, film and disc in place, FIG. 4 a top view of the disc, FIG. 5 a side view of the disc, FIG. 6 an overall perspective view of the entire system and FIG. 7 is a top view of a modified hook.

Referring to FIG. 3, the preferred mode of using the invention is as follows: the sheet material to be tied down 10 is folded around the spreading means 7, here a disc as shown best in FIGS. 4 and S. The spreading means 7 is thus substantially enveloped by the film. The

securing means, here an open side hook 1 perforated biterminally (at both ends), is passed under the spreading means, so as to hold this, and to secure the film enveloping the spreading means. A rope 5 is passed through the holes in the securing means, so as to draw this together, and the protrusion 6 around the narrower of the two holes 3 then enters the larger of the holes 2, so as to enhance the locking action and reduce play and consequent fatigue or torsional stresses. 8 in FIGS. 2 and 3 is the open space Within the securing means, into which the neck of the film enveloping the spreading means 7 is slipped. 9 is a knot on the rope. In the general perspective view, FIG. 6, 4 denotes a securing means into which more than one rope has been slipped, thus making possible a multidirectional tiedown from a single device, and 11 an object to be covered, indicated 3,467,999 Patented Sept. 23, 1969 by dotted lines, which is covered by the sheet material, and may contribute to its support.

For optimal results we prefer to use a reinforced plastic film as the sheet material, and to make the spreading means wide enough to cover at least three reinforcing strands running in each of two directions. Generally, a width of at least is necessary, and 1" is preferred, as minima.

The material of the securing means may be metal or plastic. The latter is preferred for the spreading means because of the larger contact surface which results if the spreading means is at least somewhat deformable.

The dimensions of the biterminal holes in the securing means should be adequate to permit passage of the ropes or hooks used for tying down the sheet material, and the protrusion 6 surrounding the smaller hole should be sufficiently strong to achieve a locking effect. However, this protrusion, though preferred, is not absolutely necessary for the invention as seen from FIG. 7, in which the securing means shown has holes of equal size.

In construction and application of the tie-down device and related systems subject of the present invention, there is considerable latitude in variation, without departure from the spirit and scope of this invention.

The apertures at the securing means serve a double object. A multiplicity of them may be used, to accommodate an equal multiplicity of binding means: usually ropes, possibly strings and cables or bands; when elastic binding means are desired to supply a constant pressure such as for tying down tarpaulins exposed to exceptional wind pressure such as on truck or railroad car covers, or on ships, we may employ elastic ropes, preferably having an elastic limit in excess of 50%, or rubber bands reinforced with coiled or crimped fibers, or we may use an inherently elastic substance of high strength such as the elastic polyurethane type material known to the trade as Lycra and manufactured by E. I. du Pont de Nemours & Co. However, it is necessary that the device have at least two apertures, separated from each other by a flexible connecting member of sufiicient length, form and flexibility to be able to be bent so that it will form a loop when bent so that the two said apertures are aligned with each other and held together by any suitable locking device, such as a bolt, tie rod, shackle, but preferably by a rope or other elongated flexible binding means which passes through both apertures and ties them together at the same time it serves to hold down the flexible sheet which is secured and fastened in the application of the present invention.

In order to further facilitate the alignment of the two apertures with each other, and to minimize any motion which might disturb the alignment and when repeated, lead to fatigue damage, we prefer to have one of the apertures extended to form a tubular protrusion 6 which snugly fits into the larger aperture, 2 in FIG. 2, thus securing the two apertures together in a stable alignment, which is further strengthened when the binding means is passed through them both so as to further tie them together.

The securing means may be made of any material having the requisite mechanical strength and formability, whether now known or invented at any future time, for example of steel, or of high strength plastic materials such as, for example, polyolefins such as polypropylene, polyethylene and their coand ter-polymers; polyvinyl halides, aldehyde polymers, and the like, and also of polyesters, polyethers and polyurethanes.

The strength of the flexible area between the apertures thru which the binding means will normally pass and which will be carrying a large part of the load can be enhanced by causing its molecules to become oriented, for example, by molding to a shorter length and larger cross section than required, and then drawing to the desired dimensions.

The spreading means should be large enough in at least one dimension not to pass through the loop formed by the securing means when two apertures of this, normally the terminally positioned ones, are aligned with each other and secured by the binding means going through them, or otherwise. It is preferred that it be made of a material of at least some soft or yielding properties, so as to avoid extreme point edge or corner pressures which could damage the flexible sheet material which is to be secured.

The flexible sheet material to be secured can be any flexible material having protective qualities in any one regard. For example, it could be used to secure a parachute canopy, or a life saving receptor to save persons jumping from a burning building, or simply to protect stationary machinery or Water sensitive chemicals, or to secure children to automobile seats, or to protect moving cargo exposed to strong winds, such as truck or ship deck cargo. For these latter applications elastic binding means are particularly well adapted because they exert a constant pressure and thus prevent flapping and consequent fatigue.

The invention may also be used to set up screens of transparent or other plastic to shield construction workers on the job from wind, driving rain, heat or cold.

The preferred sheet material for the majority of applications is a plastic sheet reinforced with geometrically or non-randomly arranged strands of high strength flex resistant fibers, such as cellulose, polyester, polyether, polyurethane, polyolefin, particularly polypropylene, and related, polyvinylhalide fibers, and such fibers of similar properties as may,be invented in the future.

Particularly preferred is a flexible plastic sheet consisting of a laminate of two films between which a multiplicity of ordered reinforcing fibers ordered for example in a diamond pattern are arranged so that they can move in response to stress patterns, thus supplying reinforcement automatically where most needed to meet stresses on each particular pull or impact. Such arrangements are disclosed in detail in U.S. Patent No. 2,999,041 to R. P. Lappala.

When spreading means are used in conjunction wit sheets of such reinforced films, it is preferred that they have a surface area larger than that of a circle having a diameter of at least three times the average distance between the reinforcing fibers in the film, and preferably five times as large. A disc having a diameter of at least /2 and an average thickness of at least %2" will generally prove suitable.

Having thus disclosed our invention, we claim:

1. In a tie-down device for sheet covers, a spreading means and a securing means, the latter comprising two apertures integral with a flexible connecting member, the said apertures being of difi'erent size, the smaller aperture being surrounded by a substantially tubular extension, the said extension being adapted to enter the larger of the said apertures so as to help retain the two ends of the said securing means together with the said apertures in alignment.

2. The article of claim 1 the said securing means being molded in plastic, as a single integral unit.

3. The article of claim l the said securing means having a multiplicity of apertures.

4. The article of claim 1 the said spreading means being a plastic disc having a diameter of at least /2" and an average thickness of at least %}2".

5. A system for covering articles, comprising a flexible sheet material, said sheet material being held in protective position by elongated flexible binding means, said binding means being connected to said sheet by securing means, and spreading means, said securing means comprising at least two apertures integral with a flexible connecting member, and said spreading means being dimensioned so that it cannot pass through the loop formed when the two apertures of the securing means are aligned in contact with each. other; said flexible sheet material being interposed between said securing means and said spreading means and said securing means being flexed with terminal apertures held together to form a loop.

6. As claim 5, the said binding means being elastic.

7. As claim 5, the said flexible sheet material being reinforced with oriented polymeric fibers arranged in a geometric pattern.

8. As claim 7, the said spreading means having a surface area larger than that of a circle having a diameter of at least three times the average distance between the reinforcing fibers in the sheet material.

9. As claim 5, the said terminal apertures of the securing means being held together by a rope.

10. In a tie-down device for sheet covers, a spreading means and a securing means, the latter comprising two apertures integral with a flexible connecting member, the said securing means being molded of a thermoplastic polymeric material, and then drawn, so as to orient the molecules in the connecting member between the said apertures.

11. In a tie-down device for sheet covers, a spreading means and a securing means, the latter comprising two apertures integral with a flexible connecting member, the said spreading means being large enough in at least one dimension not to pass through the loop formed by the said securing means when two of its apertures are aligned and secured substantially in contact with each other.

References Cited UNITED STATES PATENTS 601,805 4/1898 Cook. 2,472,235 6/1949 Sullivan 24245 2,999,041 9/1961 Lappala 161-49 3,330,330 7/1967 Sanderson 161-48 XR FOREIGN PATENTS 274,116 9/ 1961 France.

DONALD A. GRIFFIN, Primary Examiner U.S. Cl. X3. 1 3515 

